by Abigail Van Buren

DEAR ABBY: I am writing regarding the letter from "Sniffled Out in Indiana" (July 18), who complained about the noises her co-worker made throughout the day. True, her co-worker may suffer from an allergy or chronic post-nasal drip, but it is also possible that he has Tourette syndrome. This is a neurological disorder, the symptoms of which can include excessive throat-clearing, sniffling and other vocalizations (verbal tics), as well as eye-blinking, facial-grimacing and shoulder-shrugging (physical tics).

Most people know only the stereotypical Tourette image they see presented on TV shows and in the movies of someone shouting, cursing and thrashing about. The average person usually does not realize that most people with TS suffer from mild symptoms that are often misinterpreted as "annoying habits." This lack of understanding and education about Tourette syndrome on the part of the general public is one of the greatest obstacles for people who have this condition. -- JILL IN TITUSVILLE, N.J.

DEAR JILL: Thank you for educating me -- and, by extension, my readers. You and the other individuals who took the time to write have taught me some things I didn't know. Among them, that the Tourette Syndrome Association is a reliable resource for learning about this often misunderstood subject. Its Web site is www.tsa-usa.org. Read on:

DEAR ABBY: My son has Tourette. Any uncontrollable, repetitive sound or movement can be a sign of it. If people ask my son why he does what he is doing or have comments about it, he will explain what it is and that he can't control it.

If a person with Tourette is asked about it, he or she can "stop" it for a while because he or she is concentrating. But once the person's attention is diverted elsewhere -- such as by work or TV -- it can start again.

I hope "Sniffled Out" will help her co-worker. It's possible he does just need tissues and some medicine, but if it's Tourette, he will need her help. It's difficult to be a part of a group when you know you're annoying them. -- OPEN-MINDED IN LAS VEGAS

DEAR ABBY: The fact that her co-worker could suppress his symptoms for a time could mean the person has a form of Tourette syndrome. Tourette syndrome consists of both vocal and motor tics lasting more than six months.

Treatments are available, including medication and cognitive behavioral therapy (among others) that have been shown to be very helpful for some patients. However, other people's acceptance and understanding is perhaps the most important factor in their improvement. -- JOEL P. SUSSMAN, M.D., COLUMBIA, S.C.

DEAR ABBY: You and your readers should know that Tourette syndrome is a protected disability under the Americans With Disabilities Act, and requesting that he "stop it" would be discriminatory. His co-workers may not know about it because he isn't required to disclose his disability to them, nor can his supervisor, if he wishes it to remain confidential. No one should assume that it's a bad habit. Trust me in stating that a Tourette sufferer truly wishes it was, because bad habits can be broken -- tics cannot. -- T.S. MOM IN TEXAS

What teens need to know about sex, drugs, AIDS and getting along with peers and parents is in "What Every Teen Should Know." To order, send a business-sized, self-addressed envelope, plus check or money order for $6 (U.S. funds) to: Dear Abby -- Teen Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included in the price.)